What Is a Condensing Furnace, and How Does It Work?

HVAC Logo IconBy Tom MoorJanuary 26, 2024

Are you getting a fair deal on your HVAC quote?
Our independent team of HVAC industry insiders can score your quote

Sharing your quote takes less than a minute

HVAC technician

When selecting a heating system, you have a wide range of options to consider based on your budget, efficiency preferences, and home comfort needs. One heating option that has surged in popularity in recent years is a condensing furnace, which offers optimal comfort and reduced energy consumption. HVAC.com explains the pros and cons of condensing furnaces, shedding light on how they operate and their costs to help you determine if one is right for you.

When you receive a quote for a new furnace, QuoteScore from HVAC.com will thoroughly analyze it to determine what’s good, what’s bad, and recommend clear next steps. Your QuoteScore report will help you understand if the proposal is fair so you can buy with confidence.

How Does a Condensing Furnace Work?

Furnaces operate by burning fuel to produce heat through a combustion process, which results in the creation of hot combustion gases. As air moves across the heat exchanger, it absorbs heat before circulating back into your home’s living areas. Traditional furnaces typically have a single heat exchanger, leading to some heat loss as combustion gases are released into the atmosphere through a flue pipe.

Condensing furnaces stand out from traditional furnaces through an advanced heat exchange process. A condensing furnace employs a secondary heat exchanger that allows it to capture and condense water vapor from exhaust gases for additional heating. The release of latent heat within the home significantly improves the overall efficiency of a condensing furnace.

The condensed water is safely drained away. The remaining, now cooler, flue gases are vented through a PVC pipe.

The Pros of Condensing Furnaces

Some of the most significant benefits of opting for a condensing furnace over a traditional natural gas furnace include:

  • Enhanced Energy Efficiency: The use of a secondary heat exchanger makes condensing furnaces generally more efficient than traditional units. Condensing furnaces boast efficiency ratings ranging from 90% to over 98%, compared to the 80-85% efficiency typical of many traditional furnaces, offering long-term cost savings for homeowners.
  • Optimal Comfort: Condensing furnaces adjust their output based on the specific heating needs of a home, providing enhanced comfort.
  • Quieter Operation: Condensing furnaces typically come with variable-speed blower motors, reducing noise levels to provide a quieter and more comfortable home environment.
  • Customizable Heating Options: The variable-speed blowers and two-stage or modulating gas valves in condensing furnaces provide more precise temperature control. This allows homeowners to customize their heating needs by adjusting airflow and temperature settings to ensure personalized comfort and energy efficiency.

The Cons of Condensing Furnaces

  • Upfront Cost: With advanced technology, including secondary heat exchangers and variable-speed motors, condensing furnaces are typically more expensive upfront than traditional gas furnaces. According to ThePrice.org, additions that can increase the overall price of a condensing furnace include variable-speed blowers, two-stage or modulating gas valves, smart thermostats, and advanced filtration systems – with each feature adding about 10-20% to the total cost.
  • Venting Requirements: Condensing furnaces produce acidic condensate which requires specialized venting materials. This may require adjustments to the existing venting system or the installation of a new one. While these modifications enhance efficiency, they can pose challenges during installation, contributing to increased costs.

Final Thoughts on Condensing Furnaces

Condensing furnaces are a popular heating option for many homeowners, offering high efficiency, precise temperature control, and quiet operation through their advanced condensation process. However, carefully weigh the higher upfront cost of buying a condensing furnace with the potential long-term energy savings. Consider speaking with a qualified HVAC contractor to determine whether a condensing furnace might be right for you, your budget, and your home comfort needs.

When you receive quotes for a new furnace, QuoteScore from HVAC.com will thoroughly analyze them to determine if they are a fair deal. This analysis gives you the insight to have the right conversations with your contractor – before they start work.


Are you getting a fair deal on your HVAC quote?
Our independent team of HVAC industry insiders can score your quote

Sharing your quote takes less than a minute

HVAC.com is your trusted advisor for all things HVAC

Talk to an advisor

Available 8 AM - 5 PM Eastern Time